Various carton constructions equipped with an opening and closing side portion have been developed. However, a mass production of such cartons by automatic carton manufacturing machines has been difficult because of the complicated construction of the cartons.
It is an object of this invention to provide a novel technique to avoid this conventional defect. It is further an object of this invention to provide a carton which enables the locking portion of a support connected to a side panel to interconnect with a locking portion of another panel automatically during the carton construction.